Ismael Reyes Retana Tello

Partner, Mexico City


A client describes him as “very knowledgeable and up to date with the details of the cases and well regarded in the legal community.”
Chambers Latin America 2020


Ismael focuses on regulatory matters and administrative litigations. With more than 25 years of experience in the public sector and more than a decade at White & Case, Ismael is considered a leading specialist in constitutional and administrative law. Ismael's technical knowledge and ability to design strategies are praised by clients, who emphasize: "He is a great strategist; he knows how to identify which courses of action to pursue and which ones to avoid." Another client points out his "technical knowledge, acquired during the many years of experience that Ismael has been practicing in the administrative litigation area." Chambers Latin America, Disputes 2021.

Among the clients he represents are important institutions in the telecommunications sectors (Telefonica, Televisa, Altán, Izzi), transport (Aeroméxico, Kansas City Southern de México), agro-industrial (National Agricultural Council, National Confederation of Potato Producers, National Chamber of Sugar and Alcohol Industry), energy (Iberdrola, X-Elio, Neon), as well as various financial and governmental entities.

Recent matters on which he has worked include several high-impact and high-importance amparos solved by the Mexican Supreme Court, as well as by the specialized courts in the field of telecommunications and economic competition.

Noteworthy in his experience is Ismael's achievements with novel injunctions and judgments in amparo trials in which legal issues such as legitimate interest, amparos' collective rights and diffuse rights were analyzed for the first time. These cases established highly relevant judicial precedents. Ismael's innovative work has been recognized twice by Financial Times' "Innovative Lawyers North America" in the category of "Rule of Law and Access to Justice."

During his time in the public sector, Ismael was considered a leading specialist in constitutional and administrative law in Mexico, acting first as Director General of Legal Studies of the Presidency, then as Deputy Legal Counsel to the President and, until 2008, as Federal Deputy Attorney General for Tax Matters and Deputy Counsel to the Ministry of Finance and Public Credit (Subprocurador Fiscal Federal).

Ismael served for nine years as the Presidential delegate before the Supreme Court of Justice of the Nation, managing constitutional controversies and preparing legislative bills. While working for the Office of the Counsel to the President and the Office of the Federal Attorney General for Tax Matters, he helped to develop several initiatives for constitutional and legal reform, and to draft Presidential decrees.

Ismael is a respected academic: he served as Professor of Constitutional Law at the Universidad Panamericana and Universidad Nacional Autónoma de México (UNAM); of Mexican Law History at the Universidad Iberoamericana; and of Human Rights at the Instituto Nacional de Capacitación Penitenciaria. Currently he is a professor at CENTRO University.

Ismael has authored several books and numerous articles in specialized magazines and newspapers. He was Publishing Advisor for the Reforma newspaper in 2006, 2008 and 2011.

Ismael has worked on a pro bono basis for more than 50 organizations such as: Mexicanos Primero, Mexicanos Contra la Corrupción, Museo Universitario de Arte Contemporáneo (MUAC), Museo MACAY, Terremoto Magazzinne, and Comisión de Solidaridad y Defensa de los Derechos Humanos (Indígenas Rarámuris). He is trustee of the Board of Museo Tamayo and of Contemporary Art Patronage (Patronato de Arte Contemporáneo) and he is a Member of the Board of SOMA.

He has been recognized by various boards as a leading lawyer in administrative litigation (Chambers Latin America, 2020 and 2021; Best Lawyers, 2020 and 2021; Who's Who Legal, 2020 and 2021; Benchmark Litigation, 2020) and TMT (Latin Chambers America, 2016 to 2021 and The Legal 500 Latin America 2021).

Bars and Courts
Authorized to practice law in Mexico
Diplomatic Studies
Instituto Matias Romero
Program on Human Rights (Diplomado en Derechos Humanos)
Universidad Iberoamericana
Attorney at Law (Abogado)
Universidad Panamericana


Recent high-impact cases that included litigation before the Supreme Court of Justice ("Supreme Court") include:

Shared network (Red Compartida), 2020
Ismael successfully represented Altán Redes in the litigation initiated by Rivada Networks against the public tender in which Altán Redes was awarded the title of wholesale concession to develop and operate the Shared Network (Red compartida). This case involves complex and innovative problems in the areas of constitutional, telecommunications and public procurement. The client's successful representation in various instances, including the Supreme Court, allowed the Shared Network to begin operations in Mexico.

Take-Off and Landing Schedules ("slots"), 2020
Ismael successfully represented Grupo Aeroméxico in an amparo trial against a resolution issued by the Federal Economic Competition Commission that determined that Grupo Aeroméxico's "slots" caused anti-competitive effects and inefficiencies in the market, and imposed several remedies to reverse the effects mentioned above. This case included an amicus curiae before the Supreme Court for a constitutional dispute related to the issue.

Sugar Mills privatization, 2018
Consorcio Azucarero Caze filed numerous lawsuits against the bids of various sugar mills that were awarded to four of the most important companies in the industry, which represented 22 percent of the country's sugar production. After several years of litigation, on February 21, 2018, White & Case achieved a decisive victory before the Supreme Court of Justice: the Court, in a split decision, denied Consorcio Azucarero Caze's claim to revert the property of the sugar mills, resolutions that will allow us to secure the sale of the sugar mills, which added up to almost US$545 million.

Tarifa Cero, 2018
Ismael represented Televisa and Telefónica in a high-profile contentious matter before the Supreme Court regarding zero termination rates (fixed and mobile). Thanks to our expert stewardship of this matter, Televisa and Telefónica secured a Supreme Court ruling that prohibits the dominant agent from collecting rates for interconnection services rendered from late 2014 to 2017 from other telecom providers.


Some cases in which novel suspensions involving effects were obtained that radiated general benefits:

Mexican potato farmers protecting local crops, (ongoing)
As part of a comprehensive strategy to defend the potato sector, Ismael obtained various suspensions (2016) against the importation of potatoes into Mexico, which, due to their general effects, set an important precedent and avoided the concretization of a government policy that could have a devastating effect on potato production in Mexico. The first instance resolutions analyzed innovative aspects such as: the general effects of an amparo trial against general rules; second- and third-generation fundamental rights; and the scope of the concepts of food security and food sovereignty. Thanks to this suspension, potatoes have not been imported into Mexico for five years because of the health hazards involved. Several of these amparos are currently in the Supreme Court of Justice.

Teacher's Evaluation, 2015
Ismael represented Aprender Primero in a constitutional trial against the controversial announcement by Mexico's Ministry of Education to suspend teachers' evaluations indefinitely. Due to the suspension that was obtained, it was guaranteed that the teachers' evaluations continued. Such evaluations are a key pillar of the government's education reform as well as a constitutional obligation to ensure the quality of education rendered by public schools.

Cancelación del proyecto Corredor Chapultpec, 2015
Ismael represented several groups of neighbors in Mexico City against the urban development project known as the "Corredor Cultural Chapultepec-Zona Rosa" proposed by the Mexico City Government. This project had serious problems from an urban, environmental and cultural point of view. The injunction obtained halted definitively the implementation of the project.

Phone rates victory for Telefónica at Mexican Supreme Court, 2012
In a case heard by the Mexican Supreme Court, the court ruled to void the mobile termination rates that the Ministry of Communications and Transport required Telefónica to charge. The court's ruling set a landmark precedent for the telecommunications industry in Mexico because it recognized the full independence of the Federal Telecommunications Commission from the Ministry of Communications and Transport and gave mobile carriers more legal certainty.

Unconstitutional "Plan," 2012
Ismael represented Grupo Telefónica in litigation that obtained a favorable ruling, pursuant to which several dispositions of the Plan Técnico Fundamental de Interconexión e Interoperabilidad (the "Plan") issued by the FTC, were declared unconstitutional. Accordingly, Grupo Telefónica is the only telecommunications service provider in Mexico that is not required to comply with certain obligations set forth in the Plan. The Mexican Supreme Court issued a book entitled Relevant Decisions, which describes the aforementioned litigation as the cornerstone for setting innovative precedents and criteria regarding the authority of the FTC as regulator of the telecommunications sector.


Ismael has participated in the publication of several books:

UNO TV no es TV: Falló el Instituto Federal de Telecomunicaciones, published by Ed. Themis y BMA, 2016

Ismael wrote the foreword to El Chamizal, a 50 años de su devolución, Edited by the General Committee of the Chamber of Deputies, 2014

Authored an essay entitled "Endorsement of Broadcasting Concessions" for the Telecommunications Law Volume of the Obra Jurídica Enciclopédica, a collection of 43 volumes, published by Editorial Porrúa and the Escuela Libre de Derecho in tribute to the 100-year anniversary of the Escuela Libre de Derecho Law School

The Federal Court of Tax and Administrative Justice LXX years after the Tax Law Enactment, Ed. Tribunal Federal de Justicia Fiscal y Administrativa, México, 5 volumes, 2006, (Tribunal Federal de Justicia Fiscal y Administrativa a los LXX años de la Ley de Justicia Fiscal) (collective work)

Ismael has also written several essays, including:

"Trends and Developments" in Chambers and Partners Litigation Guide (Mexico) in 2019 and 2020

Various publications in Nexos magazine related to law, history and art: "Atomic amnesia" (March/2020), "The poor legal protection of our cultural heritage" (September/2019), "This is no longer art… or what is art?" (February/2019), "Castle without doors. Notes to understand the weather" (November/2018), "The Holy Inquisition and the trials of Caribbean pirates" (October/2019), "The Barragan diamond: An illegal proposal?" (April/2017), "The Chamizal: A Story of Perseverance and… success" (September/2014)

"Energy reform: Notes about the constitutionality of the employment of third parties in refining activities," Jurípolis, 2009, (La reforma energética: Apuntes sobre la constitucionalidad de la contratación de terceros en actividades de refinación)

"Reflections regarding the interference of the Senate in the designation of employees of the Union," Nuestra Democracia, 2007, (Reflexiones en torno a la injerencia del Senado en el nombramiento de los empleados de la Unión)

"Historical development concerning the President’s ability to make observations regarding the Federal Expense Budget," Revista Mexicana de Justicia, 2006, (Evolución histórica de la facultad del Presidente de la República para formula observaciones al Presupuesto de Egresos de la Federación)

"The scope of the resolution related to the constitutional controversy 91/2003," Nuestra Democracia, 2005, (Alcances de la resolución de la controversia constitucional 91/2003)

"Notes about the impacts of the resolutions regarding constitutional controversies and unconstitutionality actions," Jurípolis, 2005, (Apuntes sobre los efectos de las resoluciones en las controversias constitucionales y acciones de inconstitucionalidad)

"Renewal of the judicial review system," Nuestra Democracia, 2005, (La renovación del sistema de control constitucional)

Awards and Recognition

Ranked Lawyer:

Dispute Resolution: Administrative Litigation:

  • Chambers Latin America, 2020 and 2021
  • Best Lawyers, 2020 and 2021
  • Who's Who Legal, 2020 and 2021
  • Benchmark Litigation, 2020

TMT (Telecoms, Media, Technology):

  • Chambers Latin America, 2016 to 2021
  • The Legal 500 Latin America, 2021